Semiconductor processing typically involves forming one or more layers of material over a substrate and etching the layers to define various substrate features. It is desirable in some instances to etch features which essentially self-align to other substrate features due to very high etch selectivity. This reduces the precision with which mask alignment must occur. Efforts are ongoing to improve the manner in which etching in semiconductor processing, and in particular, self-aligned etching is conducted.
This invention arose out of concerns associated with improving semiconductor etching methods, and in particular self-aligned etching.